title: Electrochemical properties of yolk-shell-structured CuO-Fe(2)O(3) powders with various Cu/Fe molar ratios prepared by one-pot spray pyrolysis.
abstract: Several yolk-shell-structured CuO-Fe2 O3 powders with various Cu/Fe molar ratios have been successfully prepared under equivalent reaction conditions using a one-pot spray pyrolysis process. The Cu and Fe components are uniformly distributed throughout the powders, irrespective of composition. The Brunauer-Emmett-Teller surface areas of the yolk-shell CuO-Fe2 O3 systems increased from 5 to 16 m(2)  g(-1) if the Cu/Fe molar ratios are decreased from 3:1 to 1:3. The initial discharge and charge capacities of the yolk-shell CuO-Fe2 O3 system (Cu/Fe=1:2), showing maximum values at a constant current density of 1000 mA g(-1) , are 1436 and 1012 mA h g(-1) , respectively. After 130 cycles, the discharge capacities of the yolk-shell CuO-Fe2 O3 powders with Cu/Fe molar ratios of 1:3, 1:2, 1:1, 2:1, and 3:1 are 1159, 1151, 755, 655, and 651 mA h g(-1) , respectively. The discharge capacities of the yolk-shell and dense powder samples after 50 cycles, when subjected to a series of current density increases from 500 to 5000 mA g(-1) , are 735 and 495 mA h g(-1) , respectively.
authors.affiliation: Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea), Fax: (+82) 2-4583504.
authors.forename: Kwang Min
authors.initials: KM
authors.lastname: Yang
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Hong
authors.forename: Yun Chan
authors.initials: YC
authors.lastname: Kang
mesh_terms: D003300:Copper / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry; D005290:Ferric Compounds / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D011208:Powders
chemical_list: D005290:Ferric Compounds; D011208:Powders; C000499:ferric oxide; D003300:Copper; D007501:Iron; C030973:cupric oxide
keywords: batteries; electrodes; nanostructures; spray pyrolysis; yolk-shell powders